This invention relates generally to tobacco substitutes and more particularly to tobacco substitutes comprising cellulose.
It is known that cellulose and certain derivatives thereof can be used as tobacco substitutes to replace part or in some cases all of the tobacco in a smoking article. Cellulose, itself, is one of the main constituents of a cigarette being present to the extent of 15% to 20% by weight. Most of the cellulose is present in the tobacco, the leaf containing 5% to 11% and stems or midribs as high as 25% although the paper wrapper contributes as much as 3% of the total cellulose content.
While the cellulose in the stems sometimes causes an off taste in the smoke, the relatively small amount of cellulose in the tobacco itself is generally masked and does not produce unfavorable tastes or odors. However, it has been found that when additional cellulose is blended with tobacco, for example, by shredding conventional paper made from pulped cellulose fibers and mixing it with tobacco in a smoking article, the resulting smoke from the mixture is harsh and unpleasant, even with as little as 2% added cellulose. This would be expected in view of the acrid and harsh odors generally noticeable in smoke obtained from burning paper.
Various attempts have been made to develop cellulose tobacco substitutes that would overcome this problem by modifying the cellulose in some manner. For example, U.S. Pat. No. 3,638,660 discloses a method for producing a tobacco substitute by highly beating fibrous wood pulp containing at least 90% alpha cellulose, intimately combining the beaten pulp with certain combustion modifiers and thereafter forming a sheet therefrom which can be cut and blended with tobacco for use in smoking articles.
An example of a tobacco substitute employing a derivative of cellulose is disclosed in U.S. Pat. No. 3,461,879 wherein cellulose oxidized to eliminate compounds giving undesirable taste to the smoke is impregnated with minor amounts of a hydrated metal compound. A variation of this product is disclosed in U.S. Pat. No. 3,608,560 wherein oxidized cellulose is mixed with combustible carbon in an amount within the range of 2% to 50% by weight of the oxidized cellulose material to form a tobacco substitute.
While all of these tobacco substitutes are better than plain paper, they have the disadvantage of being expensive to produce while still leaving much to be desired insofar as approximating or duplicating the organoleptic effect obtained from tobacco smoke. Moreover, when blended with tobacco in a smoking article, the reduction in overall undesirable elements in the smoke may also not be as effective as desired.